When your air conditioning is not working or only partially working then there are three steps that can be followed to repair the system so that it will work for you.
Step 1 is to test the integrity of the pressurised systems. This checks for leaks and ensures that the refrigerant is not escaping. Until the integrity of the pressurised systems is confirmed then there is no point in charging the system with new regrigerant.
Step 2 is to recharge the air conditioning refrigerant. Assuming the pressure test in step 1 is successful then the refrigerant can be re-charged and pressurized. Once this has been completed then the air conditioning system can be functionally tested. The vast majority of aircon repairs are covered by these steps
Step 3 may be required if there is an electrical or control issue with the air conditioning. It is unlikely, but possible that having checked the pressure and recharged the refrigerant that the air conditioning is still not working. This is likely to be due to a control system malfunction. This can be investigated once the refrigerant and compressor side of the air conditioning has been tested and charged.